Thread-measuring



E. E. FOSTER. THREADMEASURING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED MAY 28 I917.

Patented Feb. 22, 1921.

3 SHEETS-SHEET I.

Fig l /A/ VE/V 717 E. E. FOSTER. THREAD MEASURING MECHANISM FOR SEWINGMACHINES.

. A P P L l C A T l 0 N F I L E D M A128. 1917. I

Q 3 SHEETS-SHEET Z- Fig 3 APPLICATION FILED MAY 28, I917- Patented Feb.22, 1921 3 SHEETS-SHEET 3.

Mvemar M nnwanp nosrnn, or BEVERLY, MASSACHUSETTS.

THREADFMEASURING- MECHANISM FOR SI]7VING-JJIACIHIIITES.

Specification of Letters Patent.

Patented Feb. 22, 1921.

Application filed May 28, 1917. Serial No. 171,344.

To (all whom it may concern:

Be it known thatI. Enwann E. Fosrnn, a citizen of the United States,residing at Beverly. in the county of Essex and State of Massachusetts,have invented certain Improvements in Thread-Measuring =Mechanisms forSewing-hilachines, of which the following description, in connectionwith the accompanying drawings, is a specification,'like referencecharacters on'the drawings indicating like parts in the several figures.

Sewing machines and particularly those intended for use on relativelyheavy work, such as harnesses, shoe soles and the like, are usuallyequippedwith a threadmeasuring mechanism designed to draw from thethread supply in each cycle of operations of the machine substantiallythe length of thread required for. a stitch. The present inventionrelates to mechanisms of this character and aims to devise a simple.accurate and thoroughly reliable thread measuring. mechanism adaptedparticularly part of to meet the requirements of sewing nachinesdesigned to operate on heavy work.

It is obvious that the length of thread required in each cycle ofoperations of a sewin g machine willvary with the thickness of the workand thelength of the stitch made. The present invention thereforecontemplates an arrangement which will automatically vary the length ofthread supplied to the sewing instrumentalities in accordance withvariations either in the thickness of the work or in the length of,stitch; but certainfeaturcs of the invention may be used to advantage inmachines in which one only of these conditions. is taken care ofautomatically.

The invention willloe readily understood from the following descrip ionof the embodiment thereof now preferred by me and the novel featureswill be pointed out in the appended claims.

in the accompanying drawings Figure 1 is. a side elevation of the upperan outsole stitching machine equipped with a thread measuring mechanismembodying this invention;

Fig. 2 is avertical cross sectional view through certain partsof thethread measuring mechanism F 3 is a transverse vertical sectional.

view on the line 3-+3, -Fig. 2;

V needle in Fig. 4B is a side elevation of the thread measuring wheel;

Fig. 5 is a vertical cross sectional view on the line 5-5, Fig. 2;

.Fig. 6 is a vertical cross sectional view of the mechanism foradjusting the length of stitch of the machine shown in Fig. 1; and

Fig. 7 is a vertical cross sectional view taken substantially on theline 66, Fig. 6.

The sewing or stitching machine shown in the drawings forms the subjectmatter of pending application Serial No. 153,161. filed March 7., 1917in the name of Charles C. Blake. A detailed description of this machineis unnecessary for the purpose of reciprocate toward and from a worksupport or throat plate 4, and a looper 6 which presents a loop ofneedle thread to the position to be caught by the hook of the needle anddrawn up through the worl A loop thrower passes this loop of thread overa. stationary shuttle located above the work and a cam-operated take uplever 8 then acts on the needle thread to set the stitch. The work isclamped during the stitch-forming operation by means of a presserfoot 10mounted on the lower end of rod 11 which slides through the frame and isacted upon by a spring 12 to hold the presser foot 10 firmly incontactwith the work. A cam-operated locking mechanism is provided tolock the presser foot in its depressed or work-clamping position whilethe stitch is being made. The position of the pressure foot 10, thus iscontrolled by the'thickness of the work and it is locked in saidposition while the stitch-forming instrumentalities act on the work.Thefeeding mechanism shown is of the charaeter disclosed in pendingapplication Serial No. 113,724, filed August 8, 1916 in the name ofCharles C. Blake. But, in the machine shown in the present applicationthe horizontal shaft 19, which operates said mechanism, is driven by anadjustable mechanism by means of which the length of each feedingmovement, and consequently the length of each stitch formed, can beadjusted. v

This driving mechanism is inclosed in housings 20 and 21 and is bestshown in Figs. 6 and 7. Referring to these figures, it will be seen thatthe upright shaft 16 has fast thereon a cam 22 having a cam path formedtherein with driving portions and holding portions. A pin wheel 24mounted fast on shaft 25 is provided with a series of radial pins orrolls which enter successively the path in the cam 22, so that theconstant rotary motion of the shaft 16 is, by this mechanism,transformed into an intermittent rotative movement of the shaft 25. Thismechanical movement is fully disclosed in pending application Serial No.

786,909, filed August 27. 1913 in the name of Charles C. Blake. Fourpinions indicated respectively at 26, 27, 28 and 29 (Fig. 6) are mountedfast on the shaft 25 and run constantly in mesh with gears indicatedrespectively at 30, 31, 32and 33, all looseiy mounted on the hollowshaft 34:. This shaft is connected through a universal joint with theshaft 19.

The respective pairsof pinions and gears are made of different gearratios and each gear is equipped with a clutch so that, while all thegears normally rotate freely on the hollow shaft 34, any one of thegears may be made effective to drive this shaft. These clutches are allalike and consequently a description of one only is necessary. As bestshown in Fig. 7, each clutch includes a hub member 36 keyed to the shaft34: and mounted within a recess formed in its respective gear. Twofriction shoes indicated, respectively, at 37 and 38 (Fig. 7) arepivotally mounted in the hub 36 close to its periphery and they areprovided with hook-shaped spring arms which enter slots formed inopposite sides of the shaft 3a and terminate in small knobs 40 that liejust within the bore of the shaft. By referring to Fig. 6 it will beseen that normally the 31 can rotate freely on the clutch. hub 36without effecting a rotative movement of the clutch, but if the ends 40of the spring arms are forced. outwardly they will apply sufficientpressure to the friction shoes 37 and 38 to cause them to grip theperipheral wall of the recess in the gear 31 and establish a drivingengagement between this gear and the clutch hub 36, thus transmittingthe rotative movement of the gear to the hollow shaft in order to renderany one of the four gears shown effective to drive the shaft 3a, aclutch actuator is provided which consists of a plunger 41 carrying ahead l2 which slides in the bore of the shaft 34. A handle 44 is fixedon the outer end of the plunger 4-1 and enables the workman to adjustthe plunger to enable any desired pair of gears to drive the worksupport. The plunger is graduated, as shown in Fig. 6, to guide theworkman in setting it properly. It will be evident from an inspection ofF 6 and 7 that wh n the plunger is pushed inwardly to its farthestposition the pinion 26 and gear 30 will be rendered effective to drivethe shaft 34 and consequently to operate the work feeding mechanism.This. pair of gears gives the shoe its slowest feeding mo 'em'ent or, inother words, produces the shortest length of stitch. As the plunger llis withdrawn from the shaft 3d the-head a2 is moved successively intoengagement with the different pairs of members i0 and throws theclutches successively into action. The gear ratios are such that thespeed of the feeding movement of the work and, consequently, the lengthof th stitches formed, is increased as the plunger is moved outwardly.

It will now be understood that thelength of the stitch made in a givencycle of opera tions. of the machine depend upon the extent of therotative movement imparted to the shaft 34 in that cycle; and that theposition of the presser foot 10 is controlled by the thickness ,of thework on which the stitch-forming instrumentalities are operating. Thethread-measuring mechanism pro-. vided by this invention is connectedwith the shaft and the presser foot 10 so that a change in the thicknessof the work or in the length of stitch is effective to change the lengthof thread drawn from the supply by the thread-measuring mechanism.

The thread T is led from a wax pot, or any convenient source of supply,over a thread controlling or feeding wheel d6 on to a guide roll 47 andthen over another roll on the end of the take up lever 8 to the looper6. variable speed mechanism which, in the construction shown includes adifferential gear mechanism. is ar 'anged to give the thread feedingwheel d6 thread feeding movements in each cycle which, as above stated,are determined in extent by the thickness of the workand the length ofstitch. The wheel is held stationary at other times and it is of such aconstruction that it grips the thread firmly and prevents any slippageof the thread over it due to the pull of the sewing instrumentalities.As clearly shown in Figs. 2 and d, the wheel 4:6 is mounted on the hubof one of the gears of the variable speed mechanism and it conof twoplates 48 and 49 spaced slightly apart by a collar and clamped on thehub by a nut 51. The plates 48 and 49 each have a series of peripheralfingers which are spaced apart and bent so'that they cross each other,as clearly shown in Fig. 2, each finger of one plate extending throughthe space between the two adjacent fingers of the other plate. AV-shaped groove thus is formed around the periphery of the wheel by theintersections of the fingers and the thread T is placed in this grooveand is given somewhat more than one complete turn around the wheel sothat it cannot slip relatively to the wheel.

The differential gear mechanism above mentioned comprises two opposedbevel gears 52 and 53 mounted fast on co-axial shafts 54 and 55,respectively, that are arranged end to end and are supported in suitablebearing brackets mounted on the machine frame. An annular bevel gear 56carries two stub shafts 57 and 58 projecting toward each other into thecircular space at the center of'the gear and-they carry two bevelpinions 59 and 60, respectively, both of which mesh with the two bevelgears 52 and 53. A pinion 62 drives the annular gear 56 and is mountedfast on an upright shaft 63, to the lower end of which is fixed anotherpinion 64' meshing with a gear 65 that is mounted fast on the hollowshaft 34 of the mechanism that feeds the work. The angular movementimparted to the shaft 34 in each cycle is transmitted through themechanism just described to the thread feeding wheel 46 and, since thegear 53 is held stationary at this time, this movement gives the wheel46 a thread feeding movement of an extent proportional to the length ofthe work feeding movement, which, of course, determines the length ofstitch.

The additional movement of the thread feeding wheel required to enableit to operate in accordance with variations in the thickness of the workis transmitted to the differential earing through the shaft which, forthis purpose,-has fixed thereon the hub or cam 68 of a roll clutch. Thehub, as shown in Fig; 3, is provided with four pockets 69, each designedto receive aroll 70, and this hub and the rolls are inclosed in a casing72 which constitutes the actuating member for the' clutch. This memberis mounted to rock concentrically with the gear 53 and a link 7 3connects this member to one arm 74 of a bell crank lever fulcrumed onthe machine frame at 7 5 and having another arm 7 6 carrying a roll thatruns in a. cam path 78 formed in a cam that rotates with the shaft 14.The arm 7 4 is slotted and a block 7 7, mounted for adjustment in thisslot. carries the pivot pin for the upper end'of the link 73. This blockalso is pivoted to the lower end of a link 79, the upper end of which ispivoted to the rearward end of a lever 80 that is fulcrumed on themachine frame at 81, see Fig. 1, and has its forward end pivotallyconnected at 82 to the presser foot rod 11.

It is obvious that the cam mechanism just described imparts a stroke offixed extent to the lever arm 74 in each cycle; and the connectionbetween the block 7 7 and the presser foot renders more or less of thisstroke ef-v fective to move the clutch actuating member 72 as thethickness of the work increases or decreases. This clutch is so designedthat practically all of the angular movement of the part 72 in onedirection is transmitted through the clutch to the shaft and, since thegear 56 is held stationary at this time, the movement so imparted to theshaft 55 will be transmitted through the gear 53 and the pinions 59 andand the gear 52 to the thread feeding wheel 46 thus moving this wheel inthe same direction that it is moved by the connections with the workfeeding mechanism. The extent of this movement obviously will dependupon the thickness of the work since, when a thick piece of work ispositioned between the presser foot 10 and the work support 4, theconnections 80 and 79 will hold the block 77 at a point farther awayfrom the axis of oscillation of the lever arm 74 than if a thin piece ofwork is being operated upon, and thus cause the cam 78 and lever 74 toproduce a greater angular movement of the clutch actuator 72 thanotherwise would be the case.

It is obvious that the pull of the take-up of the sewinginstrumentalities on the thread will tend to rotate the wheel 46 andinterfere with the thread measuring operation. In order to prevent anyaction of this kind a cam operated brake is employed which holds theshaft against rotative movement in the direction that the pull of thethread would tend to rotate it except during the period when this shaftis being positively moved by the connections with the cam 78. This brakemechanism com prises a disk or pulley 85 fixed on the shaft 55 and afriction roll 86 mounted loosely in slots formed in the bifurcated arms87 of a bell crank lever that is fulcrumed on the shaft This roll isarrangedto wedge between the periphery of the pulley 85 and a stationaryblock 88, Fig. 5, secured fast to one of the bearing brackets. The otherarm 89 of the bell crank lever is connected by a link 90 to the lowerend of a lever 91 which is fulcrumed on the machine frame at 92, Fig. 1,and the upper end of this lever carries a roll that runs on theperipheral face 93 of a cam fast on the shaft 14; A spring 94. connectedat one end to the machine frame and at its opposite end to the lever 91,holds the roll carried by the lever in contact with the cam face 93.This spring therefore normally holds the bell crank lever arm 97 in sucha position that the roll 86 binds between the pulley 85 and the part 88and prevents the shaft 55 from rotating in the direction that wouldpermit a thread feeding movement of the wheel 46. The clutch members 68,and 72 prevent any rotative movement of the shaft 55 in the oppositedirection. The cams 93 and 78 are so timed that the brake roll 86 isreleased at substantially the instant that the rotative movement of theclutch actuator 72 produced by the cam 78 is begun, and the brake is setagain at substantially the instant that this rotative movement iscompleted. The only thread feeding movements that the wheel 46 can have,therefore, are those produced by the cam 78 and by the work feedingmechanism.

The work feeding movement takes place at the very beginning of the cycleof operations of the machine and consequently the thread feedingmovement determined by the length of stitch takes place at this time.The thread feeding movement of the wheel produced by the mechanismcontrolled by the presser foot takes place very shortly there after, andthe sum of these two movements is equal to the length of thread requiredfor the stitch to be made in that cycle of operations of the machine.The entire thread feeding operation consumes only a very small fractionof the cycle. After the thread feeding operation has taken place thewheel 46 is held stationary during the remainder of the cycle and itlocks the thread against any further forward movement while the stitchis being formed and set.

Since all of the driving connections for the thread measuring mechanismare positive in their action, this mechanism operates with greataccuracy, and is very reliable. The construction illustrated also isentirely automatic in its action, any change in either the thickness ofthe work or in the setting of the mechanism to modify the length ofstitch acting automatically to effect the required change in the threadmeasuring operation necessary to cause it to measure off the length ofthread required by the changed conditions.

It is obvious that the detailed construction of the thread measuringmechanism will vary with the character and design of the machine inwhich it is used and that the invention therefore is not limited to thedetails of the construction shown.

What is claimed as new, is:

1. A thread measuring mechanism for sewing machines comprising, incombination, a thread feeding device, and operating means thereforincluding a. variable speed driving mechanism for said device,controlled in its action both by the length of stitch and the thicknessof the work.

2. A thread measuring mechanism for sewing machines comprising, incombination, a thread feeding device, differential gearing arranged todrive said device, and means acting through said gearing to cause it togive said device a thread feeding move ment in each cycle of an extentdetermined automatically by the thickness of the work and the length ofstitch.

3. A sewing machine comprising the combination with stitch formingmechanism, a presser foot and work feeding mechanism, of a threadmeasuring mechanism comprising a thread feeding device and variablespeed mechanism for operating said device controlled in its actionjointly by said presser foot and by said feeding mechanism.

4. A sewing machine comprising the eombination with stitch formingmechanism, a presser foot and work feeding mechanism, of a threadmeasuring mechanism comprising a thread feeding device, differentialgearing operative to drive said device, and means connecting saidgearing with said presser foot and also with said work feedingmechanism, said means being constructed and arranged to cause saidgearing to give said device a thread feeding movement in each cycle ofan extent substantially proportional to the thickness of the work andthe length of the stitch.

5. A thread measuring mechanism for sewing machines comprising, incombination, a. rotatable thread feeding device, and operating mechanismforsaid device constructed and arranged to cause it to feed, in eachcycle of operations of the machine, a length of thread determined by thelength of stitch and the thickness of the work.

6. A thread measuring mechanism for sewing machines comprising, incombination, a rotatable thread feeding device, and operating means forsaid device including a variable speed mechanism and intermittinglyacting actuating mechanism therefor, said operating means beingcontrolled in its action by the thickness of the work.

7. A thread measuring mechanism for sewing machines comprising, incombination, a rotatable thread feeding device, and intermittentlyacting driving mechanism for said device constructed and arranged togive said device a thread feeding movement in each cycle of operationsof the machine of an extent determined automatically by the threadrequirements forthe length of the stitch and the thickness of the work.

8. A thread measuring mechanism for sewing machines comprising, incombination, a rotatable thread feeding device and positively actingactuating mechanism for said device constructed and arranged to givesaid device a thread feeding movement in each cycle of an extent whichis varied automatically wlth changes in the length of stitch and thethickness of the work.

A thread measuring mechanism for sewing machines comprising, incombination, a rotatable thread feedingdevice and positively actingoperating means for the device including a variable speed mechanismcontrolled by the. thread requirements for the length of the stitch andthe thickness of the work.

10. A thread measuring mechanism for sewing machines comprising, incombination, a rotatable thread feeding device and operating mechanismfor said device inclnding a differential gear mechanism arranged todrive the device and positively acting power-driven means controlledautomatically by the thread requirements and constructed and arranged todrivev said device throughsaid differential gear mechanism.

, 11. A sewing machine comprising the combination with a stitch formingmechanism, a presser foot and work feeding mechanism of a threadmeasuring mechanism comprising a thread feeding device and operatingmechanism for said device includingdiiferential gearing arranged todrive the device, connections between one member of said gearing andsaid work feeding mechanism operative to give said device a threadfeeding movement in each cycle substantially proportional to the lengthof stitch, and additional connections. between another member of saidgearing and said presser foot constructed and arranged to give saiddevice" an additional thread feeding movement of an extent varying-withthe thickness of the work.

12. A thread.measuring'mechanism for sewing machines comprising, incombination, a rotatable thread feeder and operating mechanism thereforincluding a rotatable shaft connected with said feeder to drive it,adriven cam, connections between said shaft and cam operative to givethe shaft ,rota-tive movements in one direction only, andmeanscontrolled by the thickness .of the work for controlling the extentof each rotative movement imparted to the shaft'by said connections. 7

13. A thread measuring mechanism for sewing machines comprising, incombination, a rotatable threadfeeder, and operating mechanism for saidfeeder including dif ferential gearing arranged to drive the feeder, andtwo driving connections for said gearing operable through differentmembers of the gearing, one of said connections being controlled by thelength of stitch and the other by the thickness of the Work.

14. A sewing machine comprising in combination, a stitch formingmechanism, means for adjusting the length of stitch, a rotatable threadfeeding device, and operating mechanism for said device constructed andarranged to cause it to feed in each cycle of operations of the machinea length of thread varying with the thickness of the work, saidoperating mechanism including connections with said stitch adjustingmeans whereby changes in the length of stitch will effect correspondingchanges in the length of thread fed by said device.

15. A sewing machine, having, in combination, stitch forming mechanismand a work support relatively movable to transfer the point of operationof the stitch forming mechanism around thework, means for adjusting thelength of the transferring step,

' a rotatable thread feeding device, and oper

